To provide a lighting device capable of adjusting an amount of light-emission of a plurality of LEDs and making a designated space requiring illumination at optimal brightness.

The lighting device 10B has a lighting fixture 11 formed by a plurality of LEDs connected in series, and a controller 13 for adjusting brightness of the LEDs. The controller 13 is provided with a pulsating flow power generation section for generating pulsating flow power by rectifying AC input power, an output power generation section for generating output power with a designated waveform by adding AC factors to a pulsating flow factor of the pulsating flow power, a power variable section which utilizes a PWM signal and varies the output power generated by the output power generation section at designated frequency and a designated output level, and a resonant output section which retains frequency of the output power output from the output power generation section at resonant frequency by being varied with the power variable section and outputting the output power retained at the resonant frequency to the LEDs.